The most likely cause is that the Microsoft 365 trial or subscription expired, so the desktop apps are now in Unlicensed Product mode. In that state, documents can still open, but editing and creating new files are blocked.
For Office 2003 specifically, the available guidance only confirms that very old Office versions may not work properly on newer Windows versions. If the apps showing Unlicensed Product are the current desktop Office apps, use this order:
- Check whether there is an active Microsoft 365 subscription
- Close all Office apps.
- Go to Services & subscriptions.
- Sign in with the Microsoft account that was used for Office or Microsoft 365.
- Check whether a Microsoft 365 subscription is listed as active or expired.
- If it has expired, renew it, then reopen Word or Excel.
- Make sure the correct account is signed in
- If Office asks to sign in, try all personal Microsoft accounts that may have been used to buy or activate Office.
- If the wrong account is used, Office can show We couldn't find any Office products or remain unlicensed.
- Check for multiple Office versions installed
- In Windows 10 or 11, open Control Panel.
- Select Programs > Programs and Features.
- Search for office.
- If more than one Office version appears, uninstall the version that is not being used.
- Restart the PC and open Word or Excel again.
- Try the basic activation fixes
- Check that date, time, and time zone are correct in Windows.
- Run Word or Excel as administrator once.
- Update Office.
- Run the Microsoft 365 activation troubleshooter
- This is available for Microsoft 365 on Windows 10 or later.
- Run it on the same Windows PC where Office is installed and follow the prompts.
If there is no active Microsoft 365 subscription, a temporary workaround is to use the free web apps in a browser. That allows opening and working with documents online while the desktop activation issue is being resolved.
References: